What is the primary purpose of a check valve on the discharge side of a pump?

The primary purpose of a check valve on the discharge side of a pump is to prevent backflow when the pump is off. When a pump operates, it pushes water through the system, but if the pump stops running for any reason, gravity and other forces may cause water to flow back toward the pump. A check valve serves to close off the flow in the reverse direction, ensuring that water remains in the system and does not flow back into the pump. This is critical for maintaining system pressure and preventing potential damage to the pump, as backflow can lead to issues such as flooding or equipment malfunction. The check valve effectively ensures a one-way direction of flow, providing stability and efficiency in the water distribution system.